The Research Of Non-invasive Continuous Blood Pressure Measurement Methods And Systems

Cardiac ejection make blood filling the inner cardiovascular system, and cyclical contraction and relaxation of the hear make the blood forward in vessels. Blood pressure(BP) is one of the body’s most important physiological parameters, and BP changes also affected by many factors. Therefore non-invasive continuous blood pressure measurement helps to keep abreast of changes in the general laws of human work and living conditions of the heart and circulatory system performance indicators, and provides data to support the control and prevention of sudden cardiovascular disease and hypertensive diseases, for special populations. So the research of non-invasive continuous blood pressure measurement methods and systems is significant.The main work of this research is reflected in the following aspects:① The important significance of noninvasive continuous blood pressure measurement is explained in detail. The thesis also analyzes and summarizes the existing several kinds of non-invasive blood pressure measurement and the present situation of the basic method, and also shows that the pulse wave waveform generation, pulse wave, pulse wave transit time. At the same time, introduced the principle of continuous blood pressure measurement based on pulse wave transit time.②A continuous measurement system based on pulse wave transit time of the non-invasive blood pressure is designed. The lower computer includes power management circuits, pulse sensor selection, filter circuit, summing amplifier, the master processing circuit and serial data communication circuits. When measuring pulse signal using sensors, the signal passes through the filter circuit, summing amplifier for signal conditioning to ensure that the signal voltage amplitude in the MSP430 microcontroller A / D reference voltage, then the PC sends commands to control the start and stop data acquisition and transmission.③Lower computer software programs and PC graphical user interface are designed. Firstly, software program for controlling the pulse wave signal bit machine A / D sampling, serial communication is designed. With using MATLAB, the signal is processed and the feature points are identified. Then the pulse wave transit time can be calculated, at the same time the relational model between pulse wave transit time and arterial blood pressure can be obtained. Finally functions such as real-time serial communication between PC and the lower computer, waveform display, data storage, and save the new user information, parameter analysis, and playback data can be implemented with Qt under Linux.④Various experiment schemes are designed. Then calculation absolute error of our system between Omron blood pressure monitor(HEM-6131), and comparative analysis of various experimental program derives advantages and disadvantages of different experimental schemes and analysis of system accuracy, universality and extensibility.